Logicly’s 2nd Update: Flip-Flops! (and more)

Today’s update to Logicly includes the most-requested feature of all time! Seriously, I’ve been getting it ever since I first put the prototype of Logicly on my personal blog two years ago. We now have flip-flops! With this little addition, it becomes a lot easier to build more complex circuits (though I’ve seen a couple screenshots from folks who built multiple flip-flops by hand… you’re all crazy!)

Screenshot of Logicly Preview 2

Here’s a full list of what’s new in this Logicly update:

  • SR, D, JK, and T flip-flops. The SR flip-flop is a master-slave implementation with negative edge-triggering. The others are based on IC 7474 and have positive-edge triggering along with preset and clear asynchronous inputs.
  • Push Button. Generates a high signal (true) when you press the mouse down. Goes back to low signal (false) when you release.
  • Constant Low and High input signals.
  • Label. Display some helpful descriptive text in your creations. Supports multiple lines.
  • Settings Window
    • Change the size of the editing surface grid (in pixels).
    • Toggle Snap to Grid.
    • Toggle auto-start of simulation when switching to Simulate perspective. Now you can start with the simulation in a paused state.
    • Change the appearance of connection wires between curves and lines.
    • Change each of the signal colors (high, low, and unknown).
    • Change the default “float” signal (it’s how unconnected inputs are interpreted). The default is still Unknown, like before, but now you can choose High or Low as well, if you prefer.
  • Property Editor Window
    • Change update frequency of Clock control.
    • Set startup signal of Clock and Toggle Switch.
    • Change the text of the Label control.
  • Simulation Updates
    • Design perspective is no longer “powered”. Any level of simulation, even without Clocks, must be done in the Simulate perspective.
    • Advancing the simulation by a step now controls both Clocks and propagation. Previously, propagation still happened automatically when the simulation was paused, and it could theoretically get out of sync with the clocks.
    • Improved performance of propagation.
  • A new sample demonstrates how to create a ripple counter with T flip-flops. It also includes the High constant, a Push Button, and a couple of Labels.

A variety of small bug fixes got in there too. This is a very solid release with more stability and a ton of new features that I know you all will love. We’re getting closer and closer to the release of the desktop app, and I’m pretty excited.

With that in mind, what else would you like to see Logicly do? We’ve got flip-flops now, but I know everyone has more cool stuff that they’d like to see. I put up a new form for requesting features or filing bugs, and I hope you won’t hesitate to use it:

File Bug Reports and Feature Requests Here

That goes straight to my inbox, and I take all feedback very seriously. Please share your most-desired features. You can also leave a comment here on the blog too, or post something on the Logicly Facebook page (don’t forget to Like it). You can even send a tweet to @logicly. Keep the great ideas coming!


Try the first preview build of Logicly, a digital logic simulator

Today, I’m proud to announce that I’ve uploaded the first preview build of Logicly, my digital logic simulator. I originally posted what I now call “the prototype” on my blog in late 2008. At the time, it was just a fun little experiment that I put together as a bit of nostalgia. One of my professors in college used a very simple Java applet to demonstrate logic gates in his computer architecture class, but he wanted something better. At the time, the project seemed daunting. However, with several years of real-world experience under my belt, it had become a fun weekend project.

Screenshot of Logicly

Over the last couple of years, Logicly has received much interest from computer enthusiasts, students, and educators. Both Reddit and Hacker News linked to it and provided excellent feedback. Even now, my blog’s traffic and top search terms are still dominated by people looking for Logicly. I get a few emails every month with praise, feature requests, and even stories about how a some students are using Logicly with their thesis work.

Screenshot of the prototype

Thanks to all this continued interest in Logicly, I feel that it’s time to add it bit more polish and release a desktop app that includes all the features that people consistently ask me to add. I have a bit more work ahead of me, but what’s there now already surpasses the prototype in a few areas. Things like multiple selection, a pan tool, and a couple new controls (a 4-bit digit, for instance) are the most obvious. I also spent a lot of time improving the simulation code, which leads to more consistency in propagation and timing.

There’s a lot more planned too.

  • Saving and loading files. This is, by far, the most requested feature. It will only be available in the desktop app.
  • Flip-flops. These are also a very popular request. I wanted to get them working in this preview build, but there are a couple more things to tweak, and it’s not worth delaying the preview just for these.
  • Grid settings, such as size and snapping.
  • Individual clock timing settings.

If you’re interested in future releases of Logicly, please subscribe to this blog, follow @logicly on Twitter, or like Logicly on Facebook. You can also sign up for the Logicly newsletter to get the announcement via email, if you prefer.